<!DOCTYPE html>
<html lang="en">
 <head>
  <meta charset="UTF-8">
  <meta name="Generator" content="EditPlus®">
  <meta name="Author" content="">
    <meta name="keywords" content="{:seo('keywords')}"/>
    <meta name="description" content="{:seo('description')}"/>
  <title>canvas代码雨特效 | jQuery特效|手机微信网站特效| 网页特效库</title>
  <style>
    *{padding:0;margin:0}
    html{overflow:hidden}
    canvas {
      display: block;
    }
body{
    font-size: 14px;
  
    font-family: 'Microsoft YaHei', 'Times New Roman', Times, serif;
    background-color: #fff;
    padding: 0;
    margin: 0;
}
  </style>
 </head>
 <body>
  

    
    <canvas id="canvas" style="background:#111"></canvas>

    <script type="text/javascript">
        
        window.onload = function(){
            //获取画布对象
            var canvas = document.getElementById("canvas");
            //获取画布的上下文
            var context =canvas.getContext("2d");
            //获取浏览器屏幕的宽度和高度
            var W = window.innerWidth;
            var H = window.innerHeight;
            //设置canvas的宽度和高度
            canvas.width = W;
            canvas.height = H;
            //每个文字的字体大小
            var fontSize = 16;
            //计算列
            var colunms = Math.floor(W /fontSize);  
            //记录每列文字的y轴坐标
            var drops = [];
            //给每一个文字初始化一个起始点的位置
            for(var i=0;i<colunms;i++){
                drops.push(0);
            }

            //运动的文字
            var str ="javascript html5 canvas";
            //4:fillText(str,x,y);原理就是去更改y的坐标位置
            //绘画的函数
            function draw(){
                context.fillStyle = "rgba(0,0,0,0.05)";
                context.fillRect(0,0,W,H);
                //给字体设置样式
                context.font = "700 "+fontSize+"px  微软雅黑";
                //给字体添加颜色
        let hexCode = "0123456789ABCDEF";
        let text = '#' + hexCode[Math.floor(Math.random() * hexCode.length)] + hexCode[Math.floor(Math.random() * hexCode.length)] + hexCode[Math.floor(Math.random() * hexCode.length)];


                var r = Math.floor(Math.random() * 256);
                var g = Math.floor(Math.random() * 256);
                var b = Math.floor(Math.random() * 256);
          
                 //context.fillStyle = "rgba("+r+","+g+","+b+","+0.3+")"; //可以rgb,hsl, 标准色，十六进制颜色
                  context.fillStyle = text;//可以rgb,hsl, 标准色，十六进制颜色
                  //context.fillStyle ="#DDEEFF";//可以rgb,hsl, 标准色，十六进制颜色
                //写入画布中
                for(var i=0;i<colunms;i++){
                    var index = Math.floor(Math.random() * str.length);
                    var x = i*fontSize;
                    var y = drops[i] *fontSize;
                    context.fillText(str[index],x,y);
                    //如果要改变时间，肯定就是改变每次他的起点
                    if(y >= canvas.height && Math.random() > 0.99){
                        drops[i] = 0;
                    }
                    drops[i]++;
                }
            };

            function randColor(){
                var r = Math.floor(Math.random() * 256);
                var g = Math.floor(Math.random() * 256);
                var b = Math.floor(Math.random() * 256);
                return "rgb("+r+","+g+","+b+","+0.5+")";
            }

            draw();
            setInterval(draw,30);
        };

    </script>
    
    
 </body>
</html>
